Form tie assembly for concrete



Dec. 19, 1944.

H. J. KRUEPER FORM TIE ASSEMBLY FOR CONCRETE CONSTRUCTION Filed May 12, 1942 34mm JKPZ/EPER,

INVENTOR.

Patented Dec. 19, 1944 OFFICE" FORM TIE ASSEMBLY FOR GONCRETE CONSTRUCTION Harry J. Krueper, Los Angeles, Calif.

Application May 12, 1942, Serial No. 442,656

4 Claims.

This invention relates to tie rods for concrete forms, and more particularly to a form of tie assembly which can be easily and quickly removed from the concrete structure after the concrete has hardened.

In the construction of concrete structures it has been the practice to hold the sheathing and studding against outward movement under the weight of the poured concrete by means of various types of tie rods passing through the forms. After the concrete is poured and hardened the sheathing and studding are removed and the tie rods either left in place, twisted off, or the ends unthreaded and removed, leaving an intermediate section in i.

the concrete which is either left in place or removed with great effort. When the ends of the tie rods are removed, the holes left in the sides 1 of the concrete structure are filled with grout or otherwise plugged. Inasmuch as the tie or section thereof left within the structure serves no useful purpose, and, furthermore, if the plugging or grouting of the holes is not carefully done the tie wi11 oxidize and thus stain the surface It is a further object of the present invention to provide a tie rod which upon removal from the concrete, leaves a hole of a nature which permits the introduction of cement grout in a manner to produce a fluid tight seal throughout substantially the entire thickness of the wall.

Itis a further object of the present invention to provide a tie which, upon removal from the concrete, leaves a hole which can be plugged from one side of the concrete structure. I

It is a further object of the present invention to provide a tie rod which can be used on walls of difiEerent thicknesses.

This invention possesses many other advantages and has other objects which may be made more easily apparent from a consideration of the embodiments thereof shown in the drawing accompanying and forming part of the present specification. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be understood that thi deof the structure, it is desirable to provide a tie rod which can quickly and easily be completely removed from the concrete after the concrete has hardened. Also, if the type of tie is utilized which is made up of several sections threaded together,

the middle section of which is intended to be left l in the concrete, it is necessary to reassemble the ties after they are removed from the form, which is a time consuming operation, and either slows down the concreting or else requires a larger investment in ties than would be otherwise necessary. In addition to this, ties which have a section which is left embedded in the concrete must have their removable ends removed from both sides of the form, which is also a time consuming operation.

With the above limitations and deficiencies of present types of tie rods in mind, it is an object of the present invention to provide a tie rod which can be quickly and easily removed from the concrete as a unit. I

It is a further object of this invention to provide a tie rod which does not require the pulling of sections of the rod from both sides of the concrete structure.

It is a further object of the present invention to provide a tie rod which does not require reassembly before reuse.

It is a further object of the present invention to provide a tie rod which after removal does not leave a portion of the tie rod in the con-" crete.

tailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring now to the drawing:

Figure 1 is a vertical section taken through a concrete structure and the forms, showing one form of the present invention;

Figure 2 is a partial elevation of the structure shown in Figure 1, showing one end of the tie rod assembly; and,

Figure 3 is a fragmentary vertical section showing a modified form of the present invention.

The present invention comprises a tie rod proper It, which'extends through openings II in the sheathing l2 of the forms in which the concrete is to be poured. As is conventional, the sheathing is supported by -a frame comprising a plurality of studs l3 and longitudinal wales I4 provide the bearing for the tie rods Hi. Washer nuts l5 and #5 are secured to the ends of the tie rod and serve to transmit the thrust of the concrete to the tie rod. Both of these washer nuts are. preferably threaded onto the ends of the tie rod, although any form of fastening may be used to prevent movement of the washers, such as set screws passing through'the washers and bearing against the surface of. the tie rod.

In order to perm-it ready removal of the tie rod Hi from the concrete, and for other reasons hereinafter explained; thetie rod is provided with a tapered portion, said taper being sufficient to permit the easy withdrawal of the tie rod from the concrete. The taper extends over a sufiicient length of the tie rod so that substantially all of that portion of the tie rod which lies between the forms and which will be embedded in the concrete is tapered. It will be noted that this taper extends only in one direction, so that the tie rod can be removed by being driven out toward the larger end of the tapered portion. The use of a rod having this type of taper assures that the hole left in the concrete will have a continuous taper from one side of the wall to the other. Such a tapered hole is very easily plugged by grouting, from one side, and the small amount of taper produces a wedging action on the grout which assures a water tight seal.

In order to properly gauge the thickness of the wall the threaded portion N5 of the large end of the tie is provided with a plurality of holes ll spaced at suitable intervals. These holes I1 are given a definite spacing with relation to the point at which the washer nut l5 stops when it is screwed onto opposite threaded end of" the tie rod l0. Thus, the position of the inside sur-.

face of the washer nut I5 is always rendered definite with regard to the inside surface of the washer nut l5. This, together with the lumber dimensions, determines the thickness of the wall.

A nail or other suitable element i8 is inserted in a selected hole I! and the washer nut l5 threaded on the tie rod until it abuts against the nail, thus establishing the length of the rod without measurement. In assembling the device in the form, the washer nut I5 is simply threaded onto the large end of the tie rod until it strikes against the nail or pin inserted through one of the openings II, and the entire assembly passed through the form, after which the washer nut i5 is threaded onto the smaller end of the device. This washer nut I5 is tightened until it stops because of the engagement of the nut on a small shoulder on the threaded end of the rod I 8, after which double headed nails 19 are driven through openings in the flanges of the washer nuts into 1 the Wales 14. This nailing is sufficient to maintain the tie in place even during mechanical vibration of the concrete being poured, and also serves to hold the form in place, that is, to prevent the wales, studs and sheathing from moving toward each other. Any other method of maintaining the spacing can be used, but such spacing means is not normally required after the concrete is poured as the weight of the concrete is sufficient to force the forms apart as far as the tie rods will permit.

After the concrete is hardened the washer nut I5 is partially unscrewed so that its outer surface is beyond the end of the rod. Hammering on the nut will then loosen the rod suiiiciently so that afterthe nut l5 has been removed the entire tie rod can be withdrawn from the other side of the wall by hand. This withdrawal leaves a long continuously tapered hole in the cement, which, as was mentioned above, can be readily grouted. It can be seen that if the tie rod is removed in this fashion it can be immediately reinserted in another part of the form without the necessity of reassembly.

When a wall is required of a thickness such iat the length of the rod shown in Figure 1 is insufficient to extend from one washer nut to the other. the device of Figure 3 may be used to extend the range of usefulness of the tie rod II). In this figure the threaded end of the tie rod [0' is screwed into an extension 20 which has an internally threaded bore to receive the end of the rod E0. Th other end of the extension 20 is provided with suitable threads as at 2| which are engaged by the washer nut 22. The assembly remains the same as that described in connection with Figures 1 and 2, and upon disassembly it is necessary to merely unthread the tie rod H! before the device can be used again, but this requires considerably less reassembly and time than is required in conventional types of tie rods which have at least two joints to be threaded together.

I claim:

1. A form tie comprising a one piece member and spaced form engaging elements on said member for preventing spreading of the forms, said member having at one end an extended threaded portion adapted to be positioned outside of the cement receiving space between the forms for adjustably securing one of said elements to said member in different axial positions, and at the other end a threaded extremity for securing the other element to the member in a fixed position on the member, said other element having a form engaging face, said member having a taper extending from a point inside the extended threaded portion toward and substantially as far as said form engaging face of the element at the opposite end.

2. A form tie comprising a one piece member and spaced form engaging elements on said member for preventing spreading of the forms, said member having at one end an extended portion adapted to be positioned outside of the cement receivingspace between the forms and supporting one of said elements for adjustment axially of said member, and at the other end a threaded extremity for securing the other element to the member in a fixed position onthe member, said other element having a form engaging face, said memberhaving a taper extending from a point inside the extended portion toward and substantially as far as said form engaging face of the element at the opposite end.

3. A form tie as set forth in claim 1 including adjustable stop means on the extended threaded portion of said member for adjustably positioning the said one element on said member, said stop means comprising a pin member insertible selectively in any one of a plurality of transverse holes spaced axially along said member, said pin member being directly engaged by said one element and being free of restraint by the form during removal of the member from the form with the pin member in place therein.

4. A form tie as set forth in claim 1 including adjustable stop means on the extended threaded portion of said member for adjustably positioning the said one element on said member, said stop means comprising an element movable selectively to any one of a plurality of fixed positions spaced axially along said member, said element being directly engageable by the said one element and being free of restraint by the form during removal of the member from the form with the element in place thereon.

HARRY J. KRUEPER. 

